Monday, January 3, 2011

Coffee and Orange Juice for Breakfast: Safe for Diabetics?

A recent clinical study found that coffee, both regular and decaf, lowers blood sugar levels two hours after breakfast. It's not a good idea to add a lot of cream and sugar, but a small glass of orange juice make actually protect your blood vessels.


Researchers at the University of Toronto set out to explain why coffee seems to protect against the development of type 2 diabetes. Earlier studies had looked at blood sugar levels and found that drinking coffee seems to lower them, but they did not explain why. The Canadian researchers designed a study that would measure not just blood sugar levels but also levels of insulin and the storage form of insulin, pro-insulin. Here's what they found out when they gave coffee to 954 participants in the Insulin Resistance Atherosclerosis Study:

1. Drinking caffeinated coffee with breakfast resulted in lower blood glucose levels 2 hours later.
2. Drinking decaf coffee with breakfast resulted in blood glucose levels 2 hours later.
3. Drinking either kind of coffee also resulted in lower proinsulin levels 2 hours after the meal.

Proinsulin is a storage form of insulin. The pancreas makes proinsulin and seals it into tiny packets that have to be "unzipped" to release the active form of insulin. In the early stages of type 2 diabetes, often the problem is that the pancreas can't "unzip" enough of these storage packets fast enough to keep blood sugar levels low. Naturally occurring chemicals in coffee other than caffeine help the pancreas keep up the the sugars released from the digestion of the meal.

This means that coffee can help type 2's control their blood sugar levels. Insulin-dependent diabetics, however, don't enjoy the same benefit, because their bodies don't make enough insulin.

It's important, however, not to drink too much coffee with cream. Researchers at the State University of New York at Buffalo found that sugar and cream increase markers of of inflammation including nuclear factor-kappaB (NF-kappaB) binding, and the expression of SOCS3, tumor necrosis factor-alpha (TNF-alpha), and interleukin (IL)-1beta. When concentrations of these inflammatory chemicals go up, blood vessels get tight, raising blood pressure and temporarily (for up to 8 hours) increasing the risk of heart attack. The amount of cream and sugar that "significantly" increased markers of inflammation corresponded to about 300 calories. This is less than many coffee drinks at Starbucks and similar establishments, but more than a typical coffee with 1 cream and 2 sugars drunk by many with breakfast.

And what about orange juice? It is not necessary to make fresh orange juice you squeeze yourself, but diabetics need to remember that orange juice contains carbohydrates, and it's never a good idea to drink a big glass of juice. A small glass of juice, however, provides antioxidants that reduce inflammation in belly fat and very slightly reduce the coating of red blood cells that is measured with HbA1C.

Sources:

Deopurkar R, Ghanim H, Friedman J, Abuaysheh S, Sia CL, Mohanty P, Viswanathan P, Chaudhuri A, Dandona P. Differential effects of cream, glucose, and orange juice on inflammation, endotoxin, and the expression of Toll-like receptor-4 and suppressor of cytokine signaling-3.
Diabetes Care. 2010 May;33(5):991-7. Epub 2010 Jan 12.

Loopstra-Masters RC, Liese AD, Haffner SM, Wagenknecht LE, Hanley AJ.Associations between the intake of caffeinated and decaffeinated coffee and measures of insulin sensitivity and beta cell function.Diabetologia. 2010 Nov 3. [Epub ahead of print]

Ramful D, Tarnus E, Rondeau P, Robert Da Silva C, Bahorun T, Bourdon E.Citrus Fruit Extracts Reduce Advanced Glycation End Products (AGEs)- and H(2)O(2)-Induced Oxidative Stress in Human Adipocytes. J Agric Food Chem. 2010 Sep 30. [Epub ahead of print]

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